ST_CoordDim 返回 ST_Geometry 值的坐标维数。有关坐标维数的解释,参见点。
语法
db2gse.ST_CoordDim(g1 db2gse.ST_Geometry)
返回类型
整数
示例
创建具有 geotype 和 g1 列的 coorddim_test 表。 geotype 列存储 g1 几何图形列中存储的几何图形子类的名称。
CREATE TABLE coorddim_test (geotype varchar(20), g1 db2gse.ST_Geometry)
下列 INSERT 语句将样本子类插入 coorddim_test 表。
INSERT INTO coorddim_test VALUES( 'Point', db2gse.ST_PointFromText('point (10.02 20.01)', db2gse.coordref()..srid(0)) ) INSERT INTO coorddim_test VALUES( 'Linestring', db2gse.ST_LineFromText('linestring (10.02 20.01,10.32 23.98,11.92 25.64)', db2gse.coordref()..srid(0)) ) INSERT INTO coorddim_test VALUES( 'Polygon', db2gse.ST_PolyFromText('polygon ((10.02 20.01,11.92 35.64,25.02 34.15, 19.15 33.94,10.02 20.01))', db2gse.coordref()..srid(0)) ) INSERT INTO coorddim_test VALUES( 'Multipoint', db2gse.ST_MPointFromText('multipoint (10.02 20.01,10.32 23.98, 11.92 25.64)', db2gse.coordref()..srid(0)) ) INSERT INTO coorddim_test VALUES( 'Multilinestring', db2gse.ST_MLineFromText('multilinestring ((10.02 20.01, 10.32 23.98,11.92 25.64),(9.55 23.75,15.36 30.11))', db2gse.coordref()..srid(0)) ) INSERT INTO coorddim_test VALUES( 'Multipolygon', MPolyFromText('multipolygon (((10.02 20.01,11.92 35.64,25.02 34.15, 19.15 33.94,10.02 20.01)),((51.71 21.73,73.36 27.04,71.52 32.87, 52.43 31.90,51.71 21.73)))', db2gse.coordref()..srid(0)) )
该 SELECT 语句列示 geotype 列中存储的子类名和该 geotype 的坐标维数。
SELECT geotype, db2gse.ST_coordDim(g1)' coordinate_dimension' FROM coorddim_test GEOTYPE coordinate_dimension -------------------- -------------------------- ST_Point 2 ST_Linestring 2 ST_Polygon 2 ST_Multipoint 2 ST_Multilinestring 2 ST_Multipolygon 2 6 record(s) selected.